I have a Maestro debit card issued by a European bank.
Will I be able to use it to withdraw cash from ATMs and banks in Cuba?
The answer seems to be yes. On January 23, 2015 Mastercard said they will lift the transaction block on US cards in Cuba source. On June 27, 2016 the Central Bank of Cuba today authorized the use of MasterCards issued by Stonegate Bank in the US and Banco Popular of Puerto Rico in operations at ATMs in the Cuban capital source. So MasterCard is present in the country. This article mentions
A Londoner from Portugal who worked for a multinational company was also staying there for one more night. My 24-hour roommate was fluent in Spanish and English. I explained my story to her, and she said that the ATMs worked fine.
According to tripadvisor
MASTERCARDS will not be accepted in ATM's but, as with VISA cards, so long as they are issued by a non US based bank, can be used to draw cash at the counter of a Cadeca or Bank.
Whether this is outdated or not is hard to find. That's the main problem: everything online is highly suspect to be outdated.
So while it is not 100% clear whether it'll work in an ATM or not, there's a third hand very recent report it just might but even if it doesn't, it should work in a bank.
And yet, I'd only rely on this for emergencies and I would bring enough cash with me.